1. Field of the Invention
The present invention relates to a recording material, more particularly to a recording material which has a property responsive to ultraviolet rays and in which a coloring sensitivity varies in accordance with humidity.
2. Description Related to the Prior Art
As one of recording materials, a thermosensitive color recording paper for color print is well known. On a support or base of the thermosensitive color recording paper, there are yellow, magenta, and cyan coloring layers which lie on each other. The yellow coloring layer and the magenta coloring layer is provided with a fixing property in ultraviolet ray or light of a predetermined wavelength region. Accordingly, when the thermosensitive color recording paper is illuminated in light including ultraviolet ray, then the thermosensitive coloring layers are fixed such that the coloring sensitivity may vary.
In each of the yellow, magenta, and cyan coloring layers, the coloring sensitivity varies in accordance with hydrous rate. Accordingly, when an image is printed on the thermosensitive color recording paper having high hydrous rate, then the density of each yellow, magenta, and cyan color becomes inadequate and a gray balance is bad. Thus the color print is different from the original. Further, when part of the thermosensitive color recording paper has higher hydrous rate than another part, the print is made uneven.
In order to protect the thermosensitive coloring layers from moisture, scratches and dirt, a protective layer is formed on the uppermost thermosensitive coloring layer on the recording surface. Further, an opposite surface of the thermosensitive color recording paper to the recording surface may be illuminated in the light, which can pass through a support of the thermosensitive recording paper to perform the fixing of the yellow and magenta coloring layers. In order to prevent such the undesirable fixing, Japanese Patent Laid-Open Publication No. 2000-229476 describes the thermosensitive color recording paper in which an optical absorbing layer containing the ultraviolet absorbent, ultraviolet stabilizer or the like is formed on the opposite surface of the thermosensitive color recording paper, or between the support and the thermosensitive coloring layers.
In the thermosensitive color recording paper, there are a sheet type and a continuous type. In the sheet type, the thermosensitive color recording papers are piled up, and the recording surface is not exposed. Accordingly, the influence of the ultraviolet ray and the moisture on the recording surface is small. Further, in the continuous type, as the thermosensitive color recording paper is rolled, the influences of moisture and ultraviolet ray on the recording surface is small. However, the moisture and the ultraviolet ray have influences on part of the thermosensitive coloring layers near to edges of the thermosensitive color recording paper. Accordingly, coloring density changes in edge part of the obtained photo print. Further, the thermosensitive coloring layers often absorbs moistures through the support to change the coloring sensitivity of the yellow and magenta coloring layers.